CORTICAL PROJECTIONS OF AREA V2 IN THE MACAQUE

To determine the locus, extent and topographic organization of cortica l projections of area V2, we injected tritiated amino acids under elec trophysiological control into 15 V2 sites in 14 macaques. The injectio n sites included the foveal representation and representations ranging from central to far peripheral eccentricities in both the upper and l ower visual fields. The results indicated that all V2 sites project to pographically back to V1 and forward to V3, V4 and MT. There is also a topographically organized projection from V2 to V4t, but this project ion is limited to the lower visual field representation. V2 thus appea rs to project to virtually all the visual cortex within the occipital lobe. In addition to these projections to occipital visual areas, V2 s ites representing eccentricities of similar to 30 degrees and greater project to three visual areas in parietal cortex - the medial superior temporal (MST), parieto-occipital (PO) and ventral intraparietal (VIP ) areas. This peripheral field representation of V2 also projects to a rea VTF, a visual area located in area TF on the posterior parahippoca mpal gyrus. Projections from the peripheral field representation of V2 to parietal areas could provide a direct route for rapid activation o f circuits serving spatial vision and spatial attention.